A moving mechanism for a blast gun is provided which can easily move a blast gun accommodated in a blasting chamber and which can easily perform other operations from the outside thereof without leaking dust. A plurality of arm members (first input arm (21) , second input arm (22) , first output arm (31) , and second output arm (32) ) are interlocked to form an input arm (20) and an output arm (30) , each having one pair of arm members, one arm of the two arm members is pivotally attached to the other arm so as to be rotatable around an interlocked portion serving as a fulcrum, the input arm (20) is disposed outside the blasting chamber (3), and the output arm (30) is disposed inside the blasting chamber (3); in addition, the input arm (20) and the output arm (30) are interlocked to each other by an interlocking unit (40) which penetrates a top plate of a cabinet (4) , and a power transmission mechanism is provided which rotates the second arm (22) synchronously with the rotation of the input arm (20), so that a blast gun (5) fitted to the output arm (30) can be moved by operating the input arm (20).